1. Field of the Invention
The invention relates to a method for operating a counterbalancing device for a diver automatically to dive, surface or float at a prescribed or preselectable water depth.
2. Description of the Related Art
When scuba diving, that is to say using compressed air tanks, buoyancy compensator and life jacket, regulator and other items of equipment, in underwater sport the diver has to set valves manually by hand operation in order to dive, surface and float at a specific water depth. To this end, the diver weights himself down before the dive using a weight belt having lead, as required, in order to ensure that it is possible to dive. After the diver has reached the desired water depth, he fills his buoyancy compensator and life jacket via valves with air from the compressed air tank until he is floating in the water. This state is achieved when the weight of the water displaced by the diver together with his equipment is exactly as large as the weight of the scuba diver.
This setting of the desired water depth is known as counterbalancing. Counterbalancing is one of the most important diving skills, which a diver must master, in particular, in order to be able to protect himself against damage to his health, but also in order to be able to save energy underwater and to dive pleasurably. The counterbalancing operation is relatively difficult, because there is a time delay between operating the valve to fill or empty the buoyancy compensator and life jacket and the change in depth, and because, as a consequence of a change in depth due to swimming movements or water currents, the air volume in the jacket automatically changes precisely to further to amplify the positive or negative buoyancy.
A particularly critical case is surfacing, since the air in the jacket expands because of dropping water pressure, and consequently the positive buoyancy becomes ever larger. In the event of an excessively rapid and uncontrolled ascent, the danger exists of a decompression injury or of tearing of the lung.
A device for automatically limiting the rate of ascent in the case of surfacing by divers is to be taken from EP-A 41194. The device is characterized by a chamber that is connected to the interior of the life jackets and has, subdividing it, an elastically longitudinally movable, sealing partition which is connected to a valve closing part which is displaceable in a sealing manner and leads outwards and whose associated valve seat is arranged in the outer wall of the life jacket, the chamber sections formed by the partition being connected to one another by a dosing nozzle and a check valve that is open in the direction towards the closed chamber section.
A diving positive buoyancy compensator, in particular in the form of a buoyancy compensator or counterbalancing jacket for positive buoyancy compensation or stabilization and for emergency flotation of a diver during diving, can be taken from DE-A 3,644,742. The counterbalancing jacket cooperates with a safety valve arrangement which has an operating mechanism for opening a valve, the mechanism being provided with a drag line by means of which the diver can manipulate the mechanism. The drag line extends from the operating mechanism through the first inflation hose, which can be expanded and contracted in the manner of a bellows, to the inflator, which is arranged at the end of the hose. The safety valve arrangement has, moreover, effective means for sealing against water.
As a consequence of the purely mechanical operation of the counterbalancing devices, the rates of ascent and descent cannot be variably set, so that the ascent and descent cannot be optimally controlled for the diver. These devices may well be capable of rendering assistance to the diver during ascent, but they are not suitable for keeping constant a state of floating at a prescribed water depth.